Snaking robotic arm with movable shapers

ABSTRACT

Presented is a method and apparatus comprising one or more robotic members which are curvaceous or snake-like; having movable shapers through which may pass an articulable column having successive joints formed of alternating ball and socket members. The shapers can be directed up and down the articulable column, to create virtually any radius of curvature, in any direction. The robotic member may also include discrete microelectronic mechanical devices (MEMS) shapers with embedded addressable controllers. Thus the device, with computerized control is capable of negotiating a tortuous path to access the site of a given operation and to retreat along the same path, without injury to the body in which the arm is directed. Once at the work site, the articulating columns, or parts of them, may be put in compression, causing them to become rigid.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a method and means for building an improvedrobotic arm and fingers that are snake-like, and which is composed of anarticulable column, composed of segmented members that while flexibleare shaped by shaping elements through which the articulable columnpasses and discrete microelectronic mechanical systems (MEMS) that shapethe column. Once the snaking columns have reached the work site, all orparts of them are transformed into a rigid work platform by compressingvarious parts of the segmented members by means of compressing members,while still maintaining its shape.

2. Description of Prior Art

Articulable columns have long been known for use in positioningmicrometers and other measurement tools, or as electric light stands.

U.S. Pat. No. 599,543 discloses a support for incandescent electriclamps where the column is composed of a series of ball/socket members.An extension spring through the column provides tension to lock thecolumn in place. Electrical wires run inside this spring from the baseto the lamp fixture.

U.S. Pat. No. 870,429 discloses a sectional stand where a steel cable isused to maintain tension on the ball/socket members. Also a mechanism isprovided to increase or decrease tension on the cable.

U.S. Pat. No. 912,308 discloses a sectional stand using alternating bendaxis ball/socket members and a detachable means of removing the lampfixture. Also disclosed is a spirally wound steel cable which forms thetensioned flexible cable. Electrical wires run inside this cable.

U.S. Pat. No. 936,379 discloses an adjustable lamp bracket in which thearticulable column is composed of alternating ball and socket members.

U.S. Pat. No. 1,279,803 discloses a light support where a mechanism isprovided to readily change tension on an extension spring to increase ordecrease stiffness of the column.

U.S. Pat. No. 2,510,198 discloses the use of a flexible positioner as atool holder. A means is provided to adjust the cable tension. Aprotective, flexible covering over the column is also shown.

U.S. Pat. No. 3,096,962 discloses a locking device for a measuringapparatus or the like where a single cam mechanism locks both thearticulable column and the tool in place.

U.S. Pat. No. 3,529,797 discloses a supporting stand for instruments,primarily surgical instruments, in which the stand can be readilydisassembled, sterilized, and reassembled. A wedge mechanism tensionsthe articulable column cable.

U.S. Pat. No. 3,584,822 discloses a flexible column where the column canbe locked or unlocked with a lever at the free end. Electrical wires runalongside a steel compressing member inside the column. Means areprovided to prevent the column from being twisted.

The disadvantage to prior art columns is that they are not adapted toaccommodate the forces acting on the column. Consequently they tend tosag when extended out horizontally to the floor and they are difficultto adjust into new positions.

When an articulable column is held or positioned horizontally to thefloor, a large bending moment exists at the base joint of the columnfrom which the full weight of the column and its tool is cantilevered.At the free end, column joints see only a small bending moment due tothe free end weight multiplied by a short moment arm. Prior art columns(e.g. U.S. Pat. Nos. 599,543, 936,379, 2,510,198, 3,096,962, 3,168,274,and 3,584,822) built with a stack of identical ball and socket membersare not adapted to these varying forces. Because each joint isidentical, the stiffness of each joint is the same and therefore underload these columns tend to sag at the base joint where the force isgreatest. Adjustment of these columns by gripping the column at the freeend is also difficult because, if partially locked, the column remainsstiff at the free end while persistently bending at the weakest basejoint, or if tension in the column is completely released, the columncollapses.

Prior art columns in which the diameter of the ball/socket members isgreater at the base than at the free end (e.g. U.S. Pat. Nos. 870,429,912,308, and 1,279,803) acknowledge the varying forces acting in thecolumn. However, for long columns it is an unwieldy and inelegant methodand difficult to manufacture.

U.S. Pat. No. 6,860,668 discloses an articulable column design thatvaries the angle of the socket surface that interfaces with the socketelement, thereby controlling the modulus of the column at that point,for a given amount of tension. The difficulty with this design is thatthe surfaces of many of the socket joints must be machined to differentspecifications.

SUMMARY OF THE INVENTION

It is an object of this invention to provide an improved articulablecolumn construction that overcomes the difficulties of column sag andadjustment.

It is also an object of this invention to provide a method and devicethat controls the shape of the articulable member, thereby providing atool platform which can be directed down a tortuous passage, and return,without injury to the device or the body in which it is placed.

To accomplish this it is an object of this invention to provide a methodfor making the articulable column sufficiently stiff by introducing aspringing member to the centre of the column in place of or in additionto the cable, which conventional articulable columns rely on. Thisspringing member/compressing member 5 a may have, but need not have, avariable modulus from one end to the other, for example, high modulus onthe proximal end and lower modulus on the distal end, resulting in acolumn that will have stiff proximal or base joints where acting forcesare large and (2) are relatively flexible at joints near the distal orfree end where acting forces are smaller. This allows columns to bebuilt which are slender, articulable, structural members which cansupport large free end loads, and/or long column lengths. Columns builtwith this method also can be articulated in a natural, effectivefashion. It also allows the articulable column to be relativelyflexible, prior to complete compression, which allows it to be shaped,yet, remain relatively straight in those sections that are not shaped.The springing member/compressing member 5 a also gives the articulablecolumn, and robotic arm, a biased shape, usually straight, so that thecolumn returns to the biased shape once it has passed through theshaper. In some preferred embodiments the springing member/compressingmember 5 a is responsible for all or virtually all of the biased shape,while in other preferred embodiments, the biased shape is supplementedby the contribution of other components of the arm, such as thecommunicating tubes 181, 182. In other embodiments of the inventionthese said other components are designed to act as the sole springingelement in which event a compression cable, referred to as a compressingmember 5 will be required. The springing member/compressing member 5 amay be made of any materials and designs, well known to the art. Forexample, it might be made of stainless steel or superlasticnickel-titanium and be solid or tubular, or of any suitablecross-section, or be a coiled spring. In some preferred embodiments, thecompressing member 5 may also be used exclusively or in combination withcables or other members to put the segments of the articulable columninto compression, thereby making it more rigid. In other preferredembodiments, the springing member/compressing member 5 a is used solelyto provide a springing support to the articulable column, leaving thecompression of the segments comprising the said column to other members,such as compressing member 5 b, which in some preferred embodiments arecontained within the lumen of the springing element. It should be notedthat since the springing member/compressing member 5 a may also act as acompressing member, it is sometimes referred to as a compressing member.

There are many situations in which a robotic arm should move not like anarm with joints, but like a snake that can glide around obstructions onits way into the operation site, whether as part of a surgicalprocedure, or in an automobile factory assembling difficult to accessparts. There are also situations in which the arm must curl around anobstruction with a relatively small radius. In the course of gainingentry to the site and in retreating from it, the arm need only besufficiently stiff to maintain direction and position, as it enters thebody. Only when it is at the operating site need it be stiff enough toallow the distal end of the arm to exert sufficient force to carry outthe desired procedure. During entry and exit from the body the armshould actually be somewhat compliant to prevent injury to the body itcourses through.

One difficulty with previous attempts to create a snake-like robotic armis the fact that as the arm advances any curve must cascade, proximallyor down the arm, and when exiting those curves must cascade distally orup the arm. This normally requires that each segment be separatelycontrolled with cables and actuators, controlled by a computer,resulting in a vast number of cables for the various degrees of freedomat each segment. The problem multiplies as the number of turnsincreases, especially when they are in different axes.

Another difficulty with previous attempts to create a snake-like memberis that the actuators that change the shape of the member do not havesufficient strength to hold it rigid, one the member is in position, anda stable work platform is required.

The present invention includes a selected number of shapers which can bemoved up and down the articulable column and rotated around it. As thearm advances or exits the body, the shapers are given a suitable shapeand location on the column to avoid the obstruction, and then set inthat position, relative to the body, allowing the relatively flexiblearticulable column and outer skin to assume the shape of the shapercontinuously as they advance and exit, over and/or within the shapers.As they exit the shaper, they return to their biased shape (usuallystraight) and advance until the next shaper is deployed, which in turnguides them through the next curvaceous turn. Thus, the armself-computes the cascade of movements. The arm then operates in twomodes, the first, a low energy mode in which the arm flexes easily, andresponds to the shaper's directional changes; second, when the site isreached, a high energy mode, when the segments of the column are putinto compression, creating a rigid member of the required shape, thatcan stably support the tools at the distal end of the arm and exert thenecessary force to execute the work.

The present invention also includes means for controlling individualsegments 1 b of an articulable column 1, where finer control isnecessary, such as the distal tip, or fingers of a robotic arm.

In those preferred embodiments of the invention that include shapers,any number of shapers may be included in the arm. Since the shapers aresized to pass through each other, the largest shaper will generallydeployed first, the next largest shaper will pass through the first, andthen be deployed; and each succeeding smaller shaper will pass throughthose already deployed, and be deployed, until all necessary shapershave been deployed. The shapers will be deployed in a shape that avoidsany obstruction, and then stop, relative to the body in which it isinserted, allowing the articulable column, and skin, to pass through itto the next obstruction and to assume the shape of the shaper, allowingit to also avoid the obstruction. As each succeeding obstruction isencountered, another shaper is moved forward, shaped, stopped withrespect to the body and shape the articulable arm and its skin, as itmoves forward through the shapers. On retreating from the work site, thearticulable arm will pass back through each shaper, and each shaper willthen assume its pre-deployment shape, and retreat with the distal end ofthe articulable column.

Any and all of the shapers may change their shape, and their locationrelative to the articulable arm and the body, even after firstdeployment, as the operating situation may require. This may requirecoordination with the slackening of the tension of the compressingmember 5, which then allows the articulable column 1 to flex and complywith the shapes newly created by the shaping elements.

The shapers may be constructed of various materials and incorporateelectro-mechanical devices well known to the art, all being within theambit of the invention. These methods of control may be remote from theshapers or integral to them. For example, the shapers may be composed ofshape memory materials, including shape memory alloys, such asnickel-titanium, and shape memory polymers and electro-active polymers.These materials can change shape in response to heat which may bedelivered to the shaper by means well know to the art, including bymeans of optical fibers or locally by electrical means, such asresistive heating. Other materials change shape in response to changesin electric current or charge. Microelectronic mechanical systems (MEMS)made of these materials or others may be used to create shapers thatchange the shape in response to electrical or photonic inputs. All thesemethods of creating shapers are within the ambit of the invention andthe exemplar shapers herein described are only meant to instruct thosefamiliar with the art to produce snake-like robotic arms and membersthat incorporate movable and fixed shaping means, within the ambit ofthe invention.

In some preferred embodiments the snake-like robotic arm is directed byan operator that has various visual aids to assist in directing therobotic arm into and out of the body. This may include one or morecameras located on the arm and other visual aids, well know to the art.In addition, certain routines may be programmed into the computer, whichusually is part of the system, so that the arm will assume certainpre-programmed shapes as it advances into the body and while theprocedure is ongoing. The system may also use the instructions onadvancing the arm into the body, operator and computer generated, anduse these instructions to effect the efficient withdrawal of the armfrom the body.

The system may also incorporates various tactile feedback devices, whichare usually incorporated into the various drive motors and actuators andthen fed back into the computer controlled operator interfaces,including hand controls, to give feedback on the forces acting on thedistal end of the arm and the attached operating tools. These areeffected by means well known to the art.

The means herein disclosed of moving the shapers up and down thearticulable column and rotating them about it, are also meant to beexemplary, are well known to the art and are all within the ambit of theinvention. For example, instead of utilizing communicating tubes such asthose herein described 181, 182, the shapers themselves might containsmall motors and actuators, with perhaps gears that would engage cogs onthe sheath 20 of the articulable column. Likewise the rotary motion ofthe shapes around the articulable column may be effected by similarmeans such as gears driven by remote cables that engage splinesincorporated into the surface of the sheath 20 of the articulable column1 or the skin 19. The shapers and tubes in other preferred embodimentsmay not rotate to position the shaper, but rely instead on multiplecontrolling elements 17, and cable casing 17 b that are distributedaround the circumference of the retainers 15, 15 a, each controlled by aseparate electro-mechanical motor 30 or MEMS device. In one preferredembodiment of the invention, the shapers have three controlling elements17, and complementary cable casing 17 b, equally spaced around thecircumference of the spring retainers 15, 15 a. By drawing or releasingeach of the controlling elements 17, the spring 14 can be made to assumeany curve and direction of curve desired, without requiring the tube181, 182 to rotate.

Other preferred embodiments shape the articulable column directly byconnecting abutting segments, or group of segments with MEMS devicesthat contract and expand and/or bend in response to energy inputs, forexample electro-active polymers that change their shape in response toelectrical inputs. These directly controlled segments may be used inconjunction with shapers, as described above, or alone. In one preferredembodiment the shapers and directly controlled segments are usedtogether; the shapers to control the gross shape of the arm and thedirectly controlled segments for fine finger-like manipulations. Howeverthese two approaches both utilize an articulating column, which allowsfor low energy shaping and then while in the compressed mode, provides arigid member. The compressing member 5 and compressing member 5 a, asillustrated on FIG. 16, can be attached to different segments allowingfor part of the articulable column to be compressed and made rigid, byputting the compressing member into tension, while the remaining partmay remain flexible, to allow for shaping, before, it too is compressedand made rigid.

While the articulable column 1 is described in this disclosure as beingcomprised of ball and socket segments, it is to be understood that anycolumn design that is capable of being transformed from a relativelyflexible member to a relatively rigid member would be an embodiment ofthis invention and within its ambit.

In one aspect the invention provides a controllable robotic arm. Therobotic arm comprises an articulable column; at least one compressionelement; at least one shaping element; a compression control mechanismand a shape control mechanism.

The articulable column is comprised of a plurality of segments connectedtogether end-to-end and a plurality of joints between said segments.Each each segment defines a longitudinal axis and has a first end and asecond end spaced apart from one another along said axis. Each joint islocated between a first end of one segment and the second end of anadjacent segment, and is movable so as to permit variation in the axialalignment of an adjacent pair of segments.

The articulable column is transformable from a low energy state in whichsaid joints are freely movable so as to produce bending in said column,and a high energy state in which at least one of said joints iscompressed so as to constrain its movement and thereby increase rigidityin the column along at least part of its length.

The at least one compression element acts on said articulable column soas to produce compression in at least one of said joints and therebytransform said articulable column from said low energy state to saidhigh energy state.

Each of the shaping elements extends along at least a portion of thearticulable column and, when in position for actuation, extends along atleast one of said joints. Each of the shaping elements is flexible andbends when actuated so as to produce bending movement of said joint.

The compression control mechanism controls rigidity of said articulablecolumn, wherein said compression control mechanism selectively actuatesone or more of said compression elements so as to reversibly andcontrollably produce compression in at least one of said joints.

The shape control mechanism controls the shape of said articulablecolumn, and selectively actuates one or more of said shaping elements soas to reversibly and controllably produce movement in at least one ofsaid joints.

In another aspect of the invention, each of the segments comprises aball at its first end and a socket at its second end, the sockets of thesegments having a diameter sufficient to receive the balls of thesegments.

In yet another aspect of the invention, the balls and sockets have ahyperbolic shape.

In yet another aspect of the invention, the segments are annular and areeach provided with a central, axially extending aperture, the aperturesof the segments aligning to form a central passage extending between aproximal end and a distal end of the articulable column. The compressionelement comprises an elongate tensioning element extending through saidcentral passage and having a first end located at the proximal end ofthe articulable column and a second end fixed to one of the segmentsspaced from the proximal end of the articulable column. The first end ofthe tensioning element is attached to said compression controlmechanism, and the compression control mechanism controls the tension inthe tensioning element.

In yet another aspect of the invention, the tensioning element is acable and the compression control mechanism includes means forincreasing tension in the cable.

In yet another aspect of the invention, the tensioning element iscomprised of a shape memory alloy and is shorter in its heated,austenitic state than in its cooler, martensitic state, or vice versa,and the compression control mechanism includes means for heating thetensioning element to a temperature at which at least a portion of theshape memory alloy is transformed to austenite.

In yet another aspect of the invention, at least two of said tensioningelements are provided; a first one having a hollow interior and a secondone extends through the hollow interior of the first tensioning element,wherein the second tensioning element comprises a cable and has a lengthwhich is equal to or greater than a length of the first tensioningelement.

In yet another aspect of the invention, the first tensioning element hasa variable modulus so as to be more flexible at its distal end.

In yet another aspect of the invention, a plurality of said shapingelements are provided, each extending along an outer surface of thearticulable column.

In yet another aspect of the invention, a plurality of the shapingelements are comprised of hollow springs, each mounted between a pair ofannular retaining plates, wherein one of the retaining plates is mountedto an end of a cylindrical communicating tube, and wherein thearticulable column extends through said shaping elements.

In yet another aspect of the invention, the retaining plates of eachshaping element are connected together by cables at one or more pointsaround their circumference, at least one of the cables being controlledby said compression control mechanism so as to produce an off-centrecompression or expansion force in said spring and thereby cause bendingof said shaping element.

In yet another aspect of the invention, the shaping elements areslidable axially relative to the segments of the articulable column, andare also rotatable about an axis of rotation which is parallel to thelongitudinal axis of at least one of the segments.

In yet another aspect of the invention, an inner diameter of the shapingelements is varied such that the shaping elements are nestable with oneanother, such that the coil spring of a first shaping element isreceived inside the cylindrical communicating tube of a second shapingelement, and wherein bending of the spring of the first element causesbending of the tube of the second shaping element.

In yet another aspect of the invention, the hollow spring is a coilspring or an expandable mesh spring.

In yet another aspect of the invention, a plurality of said shapingelements are comprised of microelectronic mechanical devices (MEMS) andthe shape control mechanism comprises a plurality of addressablecontrollers attached to or embedded in said MEMS devices, a computerwhich controls actuation of said MEMS devices, and one or more conduitsor a signal bus through which the MEMS devices are connected to saidcomputer.

In yet another aspect of the invention, each of the shaping elementscomprises an element which is variable in shape and/or length and whichextends across at least one of said joints of the articulable column.

In yet another aspect of the invention, each of the shaping elements iscomprised of a material selected from electro-active polymers and shapememory alloys and either partly or completely surrounds said at leastone joint.

In yet another aspect of the invention, a proximal end of the roboticarm is connected to a telescoping member received within an articulatingball actuator.

In yet another aspect of the invention, a distal end of the robotic armis provided with a connector for attaching a tool.

In yet another aspect of the invention, the robotic arm comprises two ormore of said articulable columns joined end to end, wherein anelectromagnetic connector is provided between the joined ends of thecolumns and is actuated during joining of the columns.

In yet another aspect of the invention, a locking mechanism is providedfor releasably locking two adjacent segments together. The lockingmechanism comprises an annular collar formed on an inner wall of thesocket of a first segment, and one or more addressable controllers forresistively heating the annular collar. The collar may be comprised of ashape memory alloy which recovers a memorized shape when it undergoes aphase transformation between a first state and a second state; whereinthe collar defines an inner diameter at the open end of the socket, andthe collar has a diameter in said a first state which is smaller than adiameter of the collar in said second state. Resistive heating of thecollar by the addressable controllers causes the shape memory alloy ofthe collar to transform from one of said states to the other of saidstates.

In yet another aspect of the invention, the first state is an austeniticstate and the second state is a martensitic state; wherein heating ofthe collar to the austenitic state causes the collar to constrict andengage the outer surface of the ball of a second, adjacent segment.

In yet another aspect of the invention, the first state is a martensiticstate and the second state is an austenitic state; and wherein heatingof the collar to the austenitic state causes the collar to expand.

In yet another aspect of the invention, the locking mechanism furthercomprises an annular groove formed in a base portion of the ball of thesecond segment; wherein the diameter of the collar in the martensiticstate is greater than a maximum diameter of the ball; and wherein thediameter of the collar in the austenitic state is less than a diameterof a base portion of the ball, such that the collar, when heated to itsaustenitic state, becomes locked in the groove of the ball.

In yet another aspect of the invention, each of the segments of thearticulable column is provided with said locking mechanism, such thatthe locking mechanisms comprise the compression elements of the roboticarm, wherein the diameter of the collar in the martensitic state is lessthan a maximum diameter of the ball and greater than a diameter of thebase portion of the ball; such that heating of the collar to itsaustenitic state causes the ball to be drawn into the socket, therebycompressing the joint between the ball and the socket.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of three example segments 1 b in a column 1,which is known to the art. Each segment is comprised of one ball 2 andone receiving socket 3. Compressing member 5 passes through a centeraperture in the assembly, and puts the column into compression, when theoperator wishes to stiffen the column.

FIG. 2 is a sectional view of a column 1 a, known to the art, which havejoints in which are comprised of separate balls 2 a and sockets 3 a,which have two oppositely opposed sockets.

FIG. 3 is a sectional view of a means known to the art for putting thecompressing member 5 into tension, so as to compress the segments 2 aand 3 a of the column 1 a.

FIG. 4 is a cross-sectional perspective view of a springingelement/compressing member 5 a which may be springy and may have avariable modulus from the proximal end to the distal end. Thecompressing member 5 a may be tubular and have a compressing member 5 binside its lumen, and/or 5 a may also be a compressing member.

FIG. 5 is a cross-sectional perspective view of ball 2 b and receivingsocket 3 b which are not spherical, but are hyperbolic, with the resultthat when put into compression they have a preference for assuming astraight line.

FIG. 6 is a cross-sectional perspective view of articulable column 1that is placed through a gauntlet of obstructions 13.

FIG. 6 a is a cross-sectional perspective view of a shaper.

FIG. 6 b is a cross-sectional perspective view of three shapersend-to-end, that illustrate how they might shape the articulable columnillustrated in FIG. 6.

FIGS. 7 and 7 a are cross-sectional perspective views of one possibletype of shaping element, in which a spring 14, which is uncompressed inFIG. 7 a, is compressed along one part of the circumference of thespring, by tensioning controlling element 17, causing the spring 14 a tobend in the desired shape as illustrated in FIG. 7 a.

FIGS. 8 and 8 a are cross-sectional perspective view of one possibletype of shaping element, in which a spring 14, which is normallycompressed evenly around the circumference of the spring, is releasedalong only a part of that circumference, by easing the tension oncontrolling element 17, causing the spring 14 a to bend in the desiredshape as illustrated in FIG. 8 a.

FIGS. 9 and 9 a are perspective views of one possible type of shapingelement, in which a spring 14 is webbed or in expanded metal form, whichis uncompressed in FIG. 9, is compressed along one part of thecircumference of the spring, causing it to bend in the desired shape asillustrated in FIG. 9 a. This preferred embodiment, the controllingelement 17 is threaded through the tubular member(s) wholly or partlymaking up the web.

FIG. 10 and FIG. 10 a are perspective views of one possible type ofshaping element, in which only a portion of the springing element, whichis webbed or in expanded metal form, is bent by tensioning thecontrolling element 17, as illustrated in FIGS. 9 and 9 a, and theremainder of the springing element serves as the communicating tube 181.Like that preferred embodiment illustrated in FIGS. 9 and 9 a, thecontrolling element 17 can be threaded through the tubular member(s)wholly or partly making up the web.

FIG. 11 and FIG. 11 a are cross-sectional perspective views of twoshaping elements, similar to those illustrated in FIGS. 7 and 7 a, whichinclude communicating tubes 181 and 182, and which are nested togetherto form a two shaping tube column. As illustrated the said tubes 181 and182 can be rotated and moved longitudinally, with respect to each other,and with respect to any other member within or outside the said tubes.

FIG. 12 is a cross-sectional perspective view of a two nested shapingelements, including communicating tubes 181 and 182 which have insertedinto their lumens, an articulable column 1, which assumes, while in itsrelatively compliant phase, the shape imparted to it by the said twonested shaping elements.

FIG. 13 is a cross-sectional perspective view of and example of apreferred embodiment comprising two nested shaping elements, similar tothat illustrated in FIG. 12, but with the addition of a covering elementor membrane 19 and a flexible sheath 20 that enwraps the articulablecolumn 1 and provides a smooth and slippery surface for the shapingelements and communicating tubes 181 an 182 to smoothly rotate aroundthe said column and to slide up and down the said column.

FIG. 14 is a cross-sectional perspective view of the articulatinginterface 24, 29 and control unit 25 which controls the gross movementof the arm, the position of the shaping elements and the tension on themember within the articulable column that controls the arms stiffness.Provision for tactile feedback to the operator may be incorporated intothe electro-mechanical transducers/motors 30 that effect the movementsof the various arm components, or by other means well known to the art.

FIG. 15 is a perspective block diagram illustrating the typical layoutof an operating station that incorporated the snake-like robotic arm 22with articulating interface 24, 29 between the said arm and the controlunit 25, which in turn contains the actuators and tactile feedbacksensors. The said station also includes a computer to control theactuators and feedback mechanisms 26 and a workstation with handcontrols 27 and visualization means 28.

FIG. 16 is a cross-sectional perspective view of an articulating column1 that as one shaper spring 14 a partly curved and tube 181 forming theshaper. The spring 14 a is shaped by a MEMS device 17 d that changesshape in response to energy inputs delivered by conduits 17 f toembedded addressable controllers 17 e. FIG. 16 illustrates two separatecompressing members 5 and 5 a: 5 which controls the entire articulablecolumn 1, and 5 a which controls only the proximal portion. FIG. 16 alsoillustrates MEMS devices 17 d which control abutting segments 1 b of thearticulating column 1. The MEMS devices 17 d and associated addressablecontrollers are daisy-chained to minimize the number of conduits 17 f.

FIG. 17 is a cross-sectional perspective view of three modulararticulating columns that are connected to form an arm and two finger,hand-like assembly.

FIG. 18 is a block schematic of an example control system including acomputer 26, bus or conduit 17 f, MEMS device 17 d, addressablecontroller 17 e and output feedback layer 33. FIG. 18 also illustrateshow addressable controllers 17 e allow for multiple MEMS devices 17 dand feedback devices 33 operating from a single bus.

FIG. 18 a is a block schematic of an example control system showing theMEMS device 17 d and feedback layer 33 contracting in response toelectrical current applied by the addressable controller 17 e.

FIG. 19 is a cross-sectional perspective view of an articulating columnthat is externally shaped by electro-polymer MEMS devices 17 d in itslow energy flexible state and is transformed to its high energy rigidstate along selected parts by shortening the length of selected parts ofthe springing element/compressing member 5 a.

FIGS. 20 and 20 a are cross-sectional perspective views of articulatingcolumns 1 docking using a combination of electromagnets 36 a, controlledby addressable controllers 17 e and fixed magnets 36.

FIGS. 21 and 21 a are cross-sectional perspective views of articulatingcolumn 1 docking using a combination of electromagnets 36 a, controlledby addressable controllers 17 e and fixed magnets 36 to form a threefinger hand.

FIG. 22 is a cross-sectional perspective view of an articulable columnsegment 1 a with a SMA annular collar 37, illustrated in its martensiticphase in which the annular opening is relatively large.

FIG. 22 a is a cross-sectional perspective view of the same segment 1 bas illustrated in FIG. 22, except that the SMA annular collar 37 a hasbeen heated, transforming it into its austenitic phase and recoveringits memorized shape, which has a relatively smaller annular opening.

FIG. 22 b is a cross-sectional perspective view of a segment 1 b thatconnects with the segment 1 b illustrated in FIGS. 22 a and 22 b. Thereduced annular orifice 37 b, as illustrated in FIG. 22 b indexes with agroove 37 b as illustrated in FIG. 22 b, locking the two segments 1 btogether.

FIG. 23 and FIG. 23 a are cross-sectional perspective views of twoconnected and interlocking segments 1 b. FIG. 23 illustrates the twosegments 1 b when the SMA annular collar 37 is in its austenitic phaseand hence the annular collar is relatively large, allowing the ballsegment 1 b to tilt freely within the socket portion of its mate. FIG.23 a illustrates the two segments 1 b when the SMA annular collar 37 bhas been heated, transforming it into its austenitic phase andrecovering its memorized shape, which has a relatively smaller annularopening, which locks the ball and socket mates together.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIGS. 1, 2 and 3 illustrate the existing art. FIG. 1 illustrates atypical articulable column 1, which is comprised of segments 1 b, eachhaving a ball 2 on one end and a socket 3 or receiver on the other. Themovement of each segment is limited by a shoulder 7. Each segment 1 balso has a lumen 4 through which a flexible cable, the compressingmember 5 passes. One end of the cable or compressing member 5 isconnected to the most distal segment by connecting means, such as aswage 6, and at the proximal end by a spring 9 a, and turnbucklecomprised of a threaded spring retaining block 10 a threaded stud 10,thumbscrew 11 and bearing 12; all contained within a retaining tube 9.The cable or compressing member 5 is generally tightened somewhat,providing sufficient friction, with the cooperation of the spring 9 a,to arrange the articulable column, herein referred to as the “initialfriction”. Once in place the cable is further tightened so that itbecomes rigid. FIG. 2 illustrates another type of articulable columnwhich is comprised of separate balls 2 a and receivers 3 a, the latterhaving two opposed sockets, end to end.

As illustrated in FIG. 4, in one of the preferred embodiments of theinvention, the articulable column 1 includes a springingelement/compressing member 5 a which occupies the lumen of the segments1 b of the column 1, but may be larger and have the articulable column 1within its lumen. This springing element/compressing member 5 amaintains the articulable column in a predetermined shape, usuallystraight, prior to the cable or compressing member 5 being put undertension, thereby compressing the column segments 1 b. This springingelement/compressing member 5 a may also serve in place of thecompressing member 5 or supplement its function of compressing thecolumn segments 1 b. If this is so, the springing element/compressingmember 5 a is usually connected to the most distal column segment andthe other end of 5 a to the tensioning control means. In other preferredembodiments of the invention the cable or compressing element 5 b isretained, usually in the lumen of the springing element/compressingelement 5 a.

In some preferred embodiments the springing element/compressing member 5a has a variable modulus to compensate for the greater moment of forceexerted at the proximal end than at the distal end, by forces acting onthe distal end of the column 1. This is usually accomplished by simplyhaving a tapering cross-section in the springing element/compressingmember 5 a, with the greater cross-section at the proximal end and lessat the distal. Other methods, well known to the art, can also beutilized for this purpose, such as heat treating and sectioningconnected members, each having a different modulus. FIG. 4 illustrates aspringing member/compressing element 5 a which has a lumen and has atapered cross-section to accomplish this purpose.

The springing element/compressing member 5 a also serves to give thearticulable column a starting shape, usually straight, which can then bemodified by the shapers. As mentioned, this springing element may be aseparate element or may be incorporated into other components of the arm22.

FIG. 5 illustrates a special purpose ball and socket combination inwhich the interfaces between the ball 2 b and socket 3 b are notspherical, but parabolic. This causes this connection, on compression tolock into the predetermined orientation, defined by the angle of theparabolic curve to the longitudinal axis of the segments. This type ofconnection provides a very rigid coupling, which in some preferredembodiments are used at various parts of the articulating column, inplace of the spherical type, or other types well known to the art. Thistype of coupling is used in some preferred embodiments on the proximaland distal end of the arm 22.

FIG. 6 illustrates how an articulating column 1 may snake its waythrough obstructions 13 with the addition of shapers as illustrated inFIGS. 6 a and 6 b. These shapers are in most preferred embodimentsplaced on the outside of the articulating column, although they may alsobe located within the lumen 4 of the segments 1 b.

FIG. 6 a illustrates an example of a shaper being comprised of a spring14 attached at its ends to annular retainers 15 and 15 a. The shaperchanges its shape in response to a off-centre compressing force providedby the cable 17 drawing spring retainers 15 and 15 a together at onepoint on their circumference, against the opposing force of the cablecasing 17 b, which is connected to the proximal spring retainer 15 a.The shaper also includes a communicating tube 181 which is connected tothe proximal spring retainer 15 a. As this tube is rotated and relocatedvertically 18 a, the placement of the curvature of the spring 14 islikewise relocated. If a shaper is placed over the articulable column,as illustrated in FIG. 12, the shape of the shaper imparts its shapeonto the said articulable column 1. By this method the shaper can impartvirtually any curve on the articulating column, in virtually anyorientation. In some preferred embodiments the cable 17 is enclosed in aseparate lumen in the communicating tube 181, in which case the saidlumen can act as a cable casing 17 b or a separate cable casing 17 b maybe used. Flanges 16 may be used on the spring retainers 15 and 15 a tobetter communicate their orientation to the member in which they slide.

The communicating tube 181 of the shaper needs to be flexible to allowit to snake through obstacles, but yet have sufficient stiffness to turnthe shapers and serve as a stable platform for the spring retainer 5 a.Fortunately, when the articulable column is not fully stressed andflexible, it is in a low energy mode which permits the use of low energysprings 14 and relatively flexible communication tubes 181, 182. Thesetubes 181, 182 may be made of any suitable material such as plastic orsuperlastic nickel-titanium and may be webbed or ribbed to make themmore flexible in bending, yet relatively robust in turning and pushingand pulling. The design of the web or rib pattern to accomplish theseends is well known to the art.

FIG. 6 b suggests how a series of shapers (partly rendered fordiagrammatical clarity) can provide a shaping scaffold for thearticulable column 1, and if such a scaffold were held fixed, a flexiblearticulable column passing through its lumen would assume the sameshape, and avoid the obstructions 13.

FIG. 7 and FIG. 7 a illustrate how the shaper illustrated in FIG. 6 a istransformed from its original shape (FIG. 7) to its curved shape (FIG. 7a), by simply drawing the cable 17, altering the spring shape from 14 inFIG. 7 to a curved shape 14 a as illustrated in FIG. 7 a.

Depending upon how much the cable is drawn, the radius of the curve canbe determined with precision.

FIG. 8 and FIG. 8 a illustrate a shaper that starts as a compressedspring, the cable 17 and stay 17 c retaining the spring in thisposition. The spring then may have its shape altered by allowing thecable 17 to slacken a desired amount, causing the spring to expand 14 a,as illustrated in FIG. 8 b, on the side that the cable 17 is attached tothe spring retainer 15. The advantage of this arrangement is that theshapers are more compact and may be loaded into the distal end of thearm 22 prior to the arm being deployed into the body. As the proximalshaper will normally be deployed first, on entering the body, theshapers distal to it will limit the radius of turn of the distal end ofthe arm 22, until those shapers are in turn deployed. Of course theshaper springs 14 illustrated in FIGS. 6 a and 6 b may be symmetricallycompressed, by the communicating tube being pressed up sufficiently, sothat the spring retainer 15 encounters a stop 20 a in the arm, asillustrated in FIG. 13, or the spring retainer 15 encounters a moredistal shaper that remains stationary. Either of these methods may beadopted to compact the shapers during the procedure.

As mentioned above the shapers may take many forms, and FIGS. 9 and 9 aillustrate a shaper spring of the web or expanded metal type. This typeof spring can be used in place of the springs illustrated in shapersillustrated in FIGS. 6 a and 7. If the web type spring is made of hollowtubes, the cable 17 may be threaded up one or more of the struts andattached either to the distal end of the spring, or a spring retainer15. The spring 14 can then be of any spring or shape variable devicedesign known to the art, which is suitable for the purposes of theinvention, including accordion type springs and shape memory devices.

FIGS. 10 and 10 a illustrate how a web type spring 14 may be a part ofthe communicating tube 181, simplifying the design of the shapingelement. The cable casing 17 b can be used, or can be threaded through alumen in the web. The web or expanded metal comprising the spring 14 andcommunicating tube 181 can have a varying pattern that is well known tothe art and allows for the tube section 181 to resist compressing andtorquing, but allow bending, while the distal spring 14 section willallow both compression and bending.

FIGS. 11 and 11 a illustrate how two shaper elements, as illustrated inFIG. 6 a, can be nested together, with the proximal communicating tube181 being smaller in diameter than the distal communicating tube 182.Likewise any number of shaping elements may be nested together. FIGS. 11and 11 a also illustrates how each of the shapers may be rotated andrelocated distally and proximally 18 a independently. While thepreferred embodiment of the invention illustrates communicating tubes181 and 182, it should be understood that other communication means,well known to the art may be used and be within the ambit of theinvention, such as cable, rod and/or gear arrangements or actuatorsincorporated into the spring retainer 5 a, to name a few.

FIG. 12 illustrates how the shapers impart their shape onto the flexiblearticulable column 1. While the shapers are located on the outside ofthe flexible articulable column, other preferred embodiments of theinvention place the shapers inside the lumen 4 of the segments of thesaid column.

FIG. 13 illustrates a preferred embodiment of the snake-like robotic arm22, comprised of an articulable column 1, enclosed in a close fittingflexible sheath 20 that is slippery and smoothes out the joints of thecolumn segments 1 b. This sheath may be made of any suitable flexiblematerial such as plastic tubing.

In this preferred embodiment, a springing element 7, which is made ofsuperlastic nickel-titanium, is utilized as both a springing element anda compressing member to compress the abutting surfaces of the segments 1b of the articulable column 1. The said springing element 7 is from itsproximal end to its distal end to provide a variable modulus thatassists in maintaining the flexible articulable column 1 in apredetermined shape, usually straight, prior to deployment.

The robotic arm 22 also includes a skin 19 which can be removed andreplaced with a sterilized new skin, for those procedures requiring asterile instrument. A means for attaching instruments to the distal endof the 21 may be fitted to the distal segment of the articulable column1.

The cables for the instruments that are connected to the distal end ofthe said column may pass through the lumen of the said articulablecolumn 1 or inside the lumen of the skin 21, or some other convenientpassage. The robotic arm 22 includes two shaping elements, but couldcontain any number required. Prior to deployment of the arm 22, theshaping elements, illustrated in FIG. 6 a, are moved to the distal endof the arm. As the arm is inserted in the body, generally the mostproximal shaper will be deployed and vary its shape, and the shape ofthe arm, in a direction that the operator chooses, so as to avoid anobstruction. The arm 22 will then advance, through and over the saidshaper, which will remain stationary, with respect to the body. When thenext obstruction is encountered, the next most distal shaper will thenbe deployed and shaped, and the arm will move over and through the saidtwo shapers, which shall both remain stationary with respect to thebody. If there are more shapers, and they are required, each in its turnwill be deployed and shaped. When the procedure is complete, the armwill be removed in reverse sequence.

As mentioned above, the shapers may be composed of many differentmechanical and/or electro-mechanical mechanisms, all well known to theart. These mechanisms may include micro-electronic mechanical systems(MEMS) which are incorporated into the shapers themselves and causethose elements to bend in response to electronic or photonic inputs,such as shape memory tubes, micro-actuators and electro-active polymersand other electro-active materials.

FIG. 14 schematically illustrates an example of the control andarticulating interface between the robotic arm and the operator'scommand inputs. There are many methods of controlling the motion andshape of the shapers, as well as the tension of the articulable columnand the movement of all the components of the system.

In the preferred embodiment of the invention illustrated in FIG. 14, thejoint between proximal segments 2 b and 3 b may be of the hyperbolictype which ensures proper alignment between the articulable column 1 andthe control interface 24 and 25. When the articulable column iscompressed, even slightly, the joint will become straight and maintainthe proper alignment.

In the example of FIG. 14, the proximal end of the arm is connected to atelescoping member 29, its motion 29 a controlled by actuators, notshown, that allow it to move back and forth, within an articulating ballarticulator 24, that in turn can rotate in virtually all directions 24a, together providing gross motion for the arm 22. The articulating ballarticulator 24 moves within a complementary housing 25 with acomplementary spherical cavity, by actuators not shown, fordiagrammatical clarity. The motions of the various components may beprovided by actuators 30 that provide rotational and/or linear motion 30a. In FIG. 14 these take the form of servo motors that drive gears 30 cby connecting members 30 b, which gears travel in ring gears 30 d inslots 30 e. The rotational motion of the actuator outputs turn the gearswhich in turn rotate the components, such as the shapers. The linearmotion, proximally and distally up and down the arm, is provided bythese same or other actuators. In the example illustrated in FIG. 14,the sides of the gears engage the slots 30 e, communicating the linearthrust of the actuator into linear motion of the component of which theslots 30 e are a part. FIG. 14 does not include the controllers for thetools at the distal end of the robotic arm 22, and these are well knownto the art, and may be integrated into the interface illustrated. Alsothe connections and supports for the various components have not beenillustrated for diagrammatical clarity. Some embodiments of theinvention may include a spring like 9 a on FIG. 3, between the actuator30 and the drive gear 30 c for the compressing member 5, 5 a to absorbshocks and maintain the desired tension.

FIG. 15 illustrates one possible use for the snake-like robotic arm, asa surgical device. The robotic arm 22 and control interface 24, 25illustrated in FIG. 14 are part of the control system 24 a, which isattached to or includes a computer 26, and work station 27, 28. Therobotic control system includes components well known to the art,including hand controllers 27 and visual aids 28, which would includevideo screens, x-ray imagers etc. Sensory feedback to the handcontrollers would allow the operator to sense the forces acting on therobotic arm and various tools that are employed. These for the most partare provided by sensors that detect the current draw and load at theactuators.

It is to be understood that the snake-like robotic arm may be used formany purposes and is not limited to surgery. Wherever access to a worksite is tortuous, the snake arm can be used.

FIG. 16 is a cross-sectional perspective view of an articulating column1 that has one shaper spring 14 a partly curved and tube 181 forming theshaper. The spring 14 a is shaped by a MEMS device 17 d that changesshape in response to energy inputs delivered by conduits or a bus 17 fto embedded controllers 17 e, each having its own address, hereinafterreferred to as addressable controllers 17 e. For diagrammatical clarity,FIG. 16 illustrates one wire connecting a computer 26 to all of theaddressable controllers 17 e, but it should be noted that the wire,conduit or bus is actually comprised of a number of wires, asillustrated in FIGS. 18 and 18 a and described in more detail below. Theadvantage of using addressable controllers, daisy-chained together, isthat only a small number of connecting wires is required. It shouldhowever be understood that separate wires for the delivery of power andcontrol signals may be used for some preferred embodiments. Theseconduits 17 f may be in the form of tracks along which the embeddedcontrollers slide, while maintaining electrical contact, permitting themto move relative to the articulable column, using methods well known tothe art; or they may have fixed connections. It should also be notedthat some preferred embodiments may not have embedded controllers 17 e,but have separate powered control wires for each MEMS device, andrelying on integrated control by the computer 26.

FIGS. 18 and 18 a illustrate in more detail an example of connections ofone embodiment of the invention. The MEMS device 17 d, in this examplecomprises at least one electro-active polymeric element extending acrossa joint between a pair of segments. The sleeve contracts when a currentis applied to it from length illustrated as 35 a in FIG. 18 to length 35b in FIG. 18 a. In this example, the addressable controller 17 e hasthree connections 17 f(i), 17 f(ii) and 17 f(iii) running from thecomputer 26 to the addressable controller 17 e. These three connectionsform a signal bus and power to drive the MEMS device 17 d and to receivefeedback signals from a output feedback length or strain detector 33through 17 f(v), with ground 17 f(vi). This strain detector can be asimple strain gauge embedded or attached to the MEMS device 17 d and thesignal is addressed by the addressable controller 17 e. Such length orstrain detectors are well known to the art and any convenient type maybe used and be within the ambit of the invention. FIG. 18 alsoillustrates how multiple MEMS devices 17 d and feedback devices 33 canbe connected to the same bus 17 f comprised of: 17 f(i), 17 f(ii) and 17f(iii).

The MEMS devices 17 d in some preferred embodiments are composed ofelectro-active polymers and/or other materials such as shape memoryalloy (SMA) that change their shape in response to the delivery ofenergy to them. Other MEMS devices are electro-mechanical and are madefrom a combination of motors and mechanical linkages and transmissions.

FIG. 16 illustrates how a MEMS device in the form of a plurality ofelectro-active polymeric elements can impart a shape of the articulatingcolumn indirectly using a movable shaper comprised of tube 181 andcompressed spring 14 a. Some preferred embodiments do not have springsat all, but rely on the MEMS device(s) to impart a desired shape ontothe articulable column. FIG. 16 also illustrates how these MEMS devicesin the form of electro-active polymeric elements can impart shape byacting directly on abutting segments 1 b of column 1. Some MEMS devices17 d shorten or lengthen in response to an electrical impulse, acting ina similar way to the curving of the spring 14 a; others bend, andthereby impart a curved shape to the adjoining segments of thearticulable column; still others may do both. If addressable controllers17 e are used to control the power that is delivered to each separateMEMS device 17 d, and the feedback strain gauge 33, and each device hasa unique address, the computer 26 can control each MEMS device in acoordinated manner to cause the column 1 to adopt any desired shape andsnake around obstructions as the articulable column is advanced orwithdrawn around obstructions. A combination of both means of shaping(i.e. bending and changing length) the column may be used for somepreferred embodiments, although others will contain one type. It shouldbe noted that for the purpose of diagrammatical clarity only a few MEMSdevices 17 d and their associated controllers 17 e and conduits 17 fhave been shown in FIGS. 16 and 17. Typically there would be at leastthree or four such devices located around each shaping spring 14 a andaround the segment 1 b pairs, although for some preferred embodiments,any number may be used. Although the illustration 16 shows the MEMSdevices 17 d spanning a single joint between a pair of adjoiningsegments 1 b, it should be appreciated any number of segments may bespanned.

Some of these MEMS devices, such as the electro-active polymers, have athirty to forty percent strain, but exert relatively little force. TheMEMS devices 17 d are then used to shape the articulable column 1 in itslow energy state, when flexible, and then the compressing member 5, 5 acan compress the segments of the column 1, (the high energy state) toform a rigid column of the desired shape.

Some preferred embodiments have a combination of MEMS devices thatexhibit large strain and low power with others that exhibit high powerand low strain. For example, MEMS devices 17 d that have high rates ofstrain, but exert low force, might connect segments that are separatedby one or more intermediate segments. This MEMS device might be of thepolymer type, referred to above. These MEMS devices would be responsiblefor imparting shape onto the articulable column 1. This arrangementwould also include MEMS devices 17 d which would have low strain rates,but exert high forces. These MEMS devices could connect adjoiningsegments 1 b of the articulable arm 1 and be responsible for compressingand relieving the adjoining segments 1 b of the articulable arm 1,making it more rigid and more flexible, respectively. These compressingMEMS devices would act in lieu of or in addition to the compressingmembers 5 and 5 a. In some preferred embodiments the MEMS device 17 dwould be incorporated into the segments 1 b themselves, in which casethe energy that causes the MEMS devices to change shape would causeadjacent segments to lock together. For example, the ball 2 of onesegment 1 b could expand inside the socket 3 of an adjacent segment 1 b,causing them to lock together, but any other convenient method may beadopted and be within the ambit of the invention. It should be notedthat MEMS devices 17 d that exhibit both sufficiently high rates ofstrain and high force potentials could be used for both purposes and beconnected to any convenient segments 1 b of the articulable column 1.This arrangement of shaping (the low energy state) and making thearticulable arm rigid (the high energy state), allows any part of thearm to be placed in either of the two states. In these examples, thehigh energy state is created by the higher friction created betweensegments 1 b which resists relative motion and the low energy stateoccurs when this friction is reduced.

FIG. 19 illustrates an articulable arm in which the low energy shapeforming is produced by MEMS devices 17 d, addressable controllers 17 e,and conduits or bus 17 f daisy-chained in a scheme similar to thatillustrated in FIG. 18. The MEMS devices for this purpose in somepreferred embodiments are of the large strain, low force type, such aselectro-active polymeric elements. The springing element/compressingmember 5 a in some embodiments of the invention is a tube comprised of ahigh force, low strain material such as shape memory alloy (SMA) inwhich the addressable controllers 17 e control the flow of electricalcurrent to the SMA tube and the springing element/compressing member 5 athereby resistively heating all or part of the SMA tube. FIG. 19 aillustrates such a springing element/compressing member 5 a contained inthe articulable column 1 illustrated in FIG. 19. The SMA tube whenheated above the Austenitic finish temperature, exhibits shape recoveryand assumes a shorter shape recovered Austenitic length, whichcompresses the articulable column 1, along that part of the tube that isheated. When the addressable controllers 17 e stop the flow of current,the SMA cools by ambient cooling below its Martensitic finishtemperature, reassuming its longer Martensitic shape, reducing thecompression between the segments 1 b and thereby causing the articulablecolumn 1 to become flexible in those parts so cooled. Other preferredembodiments of the invention utilize other materials that shorten inlength in response to current flow, without significant heating, for thespringing element/compressing member 5 a, but exhibit sufficiently highforces to compress and thereby stiffen the articulable column, thesematerials being well known to the art.

In other embodiments of the invention compressing members 5, 5 a will beutilized. FIG. 16 also illustrates two separate compressing members 5and 5 a: 5 which controls the entire articulable column 1, and 5 a whichcontrols only the proximal portion. Some preferred embodiments willcontain any number of compressing members attached to various portionsof the articulating column 1, depending upon the use to which it is put.

In some preferred embodiments, as in FIG. 16, the springingelement/compressing member 5 a may take the form of a sheath for theother compressing member 5, which is a cable. These may be used incombination to put various portions of the articulable column intocompression, thereby making it rigid, or by relaxing the compressiveforce, causing it to become more flexible. If the springingelement/compressing member 5 a in FIG. 16 is connected to an articulablecolumn only at its distal end 17 g, it could act to tension all thosesegments from the point of connection to the proximal end of thearticulable column 1. This springing element/compressing member 5 acould also act as a sheath for the second compressing member 5 and ifthe springing element/compressing member 5 a was not put into tension,but into compression as compressing member 5 is put into tension, onlythat portion of the articulable column distal from connection point 17 gwould become rigid. Also, one can readily appreciate that in thisembodiment, if both 5 a and 5 are put into tension, thereby putting allthe segments 1 b of articulable column 1 into compression, the entirecolumn would become rigid. It can then be appreciated that the points atwhich the compressing members are connected to the segments 1 b could bemade movable by using methods well known to the art, for example, athreaded connecting element turning in a threaded lumen, formed withinthe lumen of the articulable column. These threaded connecting elementscould be located at the distal end of the compressing members 5 or 5 aand by varying the point of connection; the desired portion of thearticulable column could be compressed and made rigid.

While FIG. 16 illustrates a single articulable column 1, it should benoted that several such articulable columns, forming fingers, may beconnected to a single articulable column 1, with snap connectors 31,forming an arm, as illustrated in FIG. 17. FIG. 17 illustrates twomodular fingers, each with integrated control interface 25 a, which maycontain the actuators or motors 30 that control the tension imparted tothe compressing members 5, 5 a. In some preferred embodiments, theintegrated control interface is dispensed with, for example, those thatutilize MEMS 17 d, to provide the compressive forces for compressing thearm segments 1 b, in lieu of the compressing members and associatedmotors 30. In FIG. 16, the conduit 17 f connects the embeddedaddressable controllers 17 e and MEMS devices 17 d with the computer 26.Any number of modular articulable columns 1 may then be arranged intoany convenient conformation. As can be readily appreciated, theconnecting points between the various modules may be made with snap onand off connectors 32, well known to the art, making remote assembly ofthe modules possible. For some uses, this assembly may take place in abody cavity when the access port does not allow the complete assembly tobe inserted. It should be noted that the lower articulable column 1,referred to as the arm, illustrated in FIG. 17, is only illustrated inpart, and will contain a control interface 24, 25 as illustrated in FIG.14.

The fact that the columns can be separately made rigid, allows for thefingers to act in their low energy mode, in which they are flexible,grasping an object with a small force, imparted by the MEMS devices 17d, then made rigid, by compressing that portion of the articulablecolumn, with the compressing members 5 or by other methods, describedherein. Finally, a larger force applied by a more powerful shaper, orother motive device acting on the now rigid fingers can cause thefingers to squeeze the object with a greater force than would bepossible with electro-active polymer MEMS devices 17 d that areconnected to the segment 1 b pair. For example, in FIG. 16, the shaperwith compressed coil 14 a could include a shape memory alloy (SMA) MEMSdevice 17 d that has low strain but that is able to exert significantforce. This shaper could deflect the articulable column, while thedistal part of the column has been made rigid, above connection 17 g, bythe compression of those segments 1 b above connection 17 g, bycompressing element 5, as described above, while the proximal portioncontrolled by the low strain, but high force MEMS device 17 d, remainsrelatively flexible.

Tools, for example, scalpels and forceps, can be added to the distal endof the articulable column 1, and the motion of these can be controlledby the motion of the arm and also by extension of the conduit 17 f, andMEMS devices 17 d and addressable controllers. Snap type connectors 31and 32 can connect the said implements to the distal end of thearticulable arm 1, and the conduit lines, respectively. These connectorsmay themselves be MEMS devices 17 c, made for example of shape memoryalloy (SMA) which clamp or swage the adjoining modules together,controlled by an addressable controller 17 e and computers 26.

As illustrated in FIGS. 20 and 20 a, in some implementations of theinvention, each module may have an electro-magnet 36 a at one of theconnecting ends, being a MEMS device 17 d with addressable controller 17e, which would control its state and perhaps polarity, while at theother end a fixed magnet, exhibiting opposite polarity. Once energizedthe electro-magnet at the end of the first segment would attract anothersegment, the second segment, having a fixed magnet 36, exhibitingopposite charge. The geometry of the two ends are such that they locktogether at a predetermined relative angle and orientation, which alignsand connects any electrical or photonic connections 32. Once connected,the electromagnetic end of the second segment 36 b is activated and thenconnects with a third segment presenting its fixed magnetic end, and soon ad infinitum until all available segments are connected. This wouldallow the modules to self-assemble, as each end of the segments ofopposite polarity, would attract one another, and prevent the lockingtogether of more than one segment. While this example includes fixedmagnets, electro-magnets that are activated by induction could be usedas well by methods well known to the art, and these would be within theambit of the invention. Obviously, those preferred embodiments thatincorporate magnets, must not be made of materials that would beinadvertently attracted to the magnet 36 or 36 b. Once locked togetherby magnetic force, additional connecting force could be effected by MEMS17 d type annular collars, incorporated into the ends of the modules.For example, FIG. 22 illustrates a SMA annular collar 37 that, whenheated by resistive heating by energy supplied by an addressablecontroller 17 e, recovers its memorized shape as it becomes austenitic,thereby reducing the diameter of annular opening 37 a as illustrated inFIG. 22 a. This reduced annular orifice indexes with a groove 37 b of anadjacent segment 1 b, as illustrated in FIG. 22 b, locking the twosegments 1 b together.

FIG. 23 and FIG. 23 a illustrate two connected and interlocking segments1 b which interact similarly to those illustrated in FIGS. 22, 22 a and22 b, except that they interlock and thereby obviate the necessity for atensioning cable 5. FIG. 23 illustrates two segments 1 b when the SMAannular collar 37 of a first segment 1 b is in its austenitic phase andhence the annular collar is relatively large, allowing the ball of anadjacent segment 1 b to tilt freely within the socket portion of itsmate. FIG. 23 a illustrates the two segments 1 b when the SMA annularcollar 37 b has been heated, transforming it into its austenitic phaseand recovering its memorized shape, which has a relatively smallerannular opening and locks the ball and socket mates together. It can bereadily appreciated that embodiments of the invention that include theseinterlocking segments illustrated in FIGS. 23 and 23 a permit theselective locking together of interfacing segments 1 b with addressablecontrollers 17 e. It should also be noted that this type of interlockingsegment can be used in any of the preferred embodiments hereindescribed. For example, groups of segments 1 b as shown in FIGS. 23 and23 a may be shaped by shapers similarly to those illustrated in FIG. 12,MEMS devices 17 d as illustrated in FIG. 16, or any other suitableshaper.

It should also be noted that some preferred embodiments have several SMAannular collars incorporated into or forming the ball and socket joints,rather than just one, as illustrated in FIGS. 23 and 23 a.

Fabricated articulable columns 1 from these types of interlockingsegments 1 b is well known to the art. For example, the interlockingsegments 1 b may be pressed together while the annular collar is in thephase in which the annular opening is relatively large and the socketportion of the segment 1 b is sufficiently elastic that it can bepressed over the socket portion of its mating segment 1 b. The elasticsocket portion then recovers to loosely envelope the ball portion of themating segment 1 b.

FIGS. 21 and 21 a are similar to those articulable columns 1 illustratedin FIGS. 20 and 20 a, except that three fingers port to each other toform a hand.

While the addressable controllers 17 e described herein are connected toeach other and to computer 26 by conduits 17 f, it should be appreciatedthat wireless connections between the components could be used in wholeor in part and be within the ambit of the invention.

While reference has been made to certain types of MEMS devices, itshould be understood that this includes the whole class of smartmaterials and micro-machine devices that can act on the articulable armto effect shapes, and all would be within the ambit of the invention.

Is to be understood that the examples of preferred embodiments of theinvention described herein are comprised of various elements and thatother preferred embodiments may contain various combinations of thoseelements and be within the ambit of this invention. For example, somedrawings for diagrammatical clarity do not include covering skins ormembranes and others do not include shapers.

While the present invention has been described in conjunction withpreferred embodiments, it is to be understood that modifications andvariations may be resorted to without departing from the spirit andscope of the invention as those skilled in the art will readilyunderstand. Such modifications and variations are considered to bewithin the purview and scope of the inventions and appended claims.

1. A controllable robotic arm, comprising: (a) an articulable columncomprised of: (i) a plurality of segments connected together end-to-end,wherein each segment defines a longitudinal axis and has a first end anda second end spaced apart from one another along said axis; (ii) aplurality of joints between said segments, wherein each joint is locatedbetween a first end of one segment and the second end of an adjacentsegment, and wherein each joint is movable so as to permit variation inthe axial alignment of an adjacent pair of segments; wherein saidarticulable column is transformable from a low energy state in whichsaid joints are freely movable so as to produce bending in said column,and a high energy state in which at least one of said joints iscompressed so as to constrain its movement and thereby increase rigidityin the column along at least part of its length; (b) at least onecompression element which acts on said articulable column so as toproduce compression in at least one of said joints and thereby transformsaid articulable column from said low energy state to said high energystate; (c) at least one shaping element, each of which extends along atleast a portion of the articulable column and, when in position foractuation, extends along at least one of said joints; wherein each ofsaid shaping elements is flexible and bends when actuated so as toproduce bending movement of said joint, wherein said shaping element isoperatively configured to slide axially relative to said segments ofsaid articulable column; (d) a compression control mechanism forcontrolling rigidity of said articulable column, wherein saidcompression control mechanism selectively actuates one or more of saidcompression elements so as to reversibly and controllably producecompression in at least one of said joints; and (e) a shape controlmechanism for controlling shape of said articulable column, wherein saidshape control mechanism selectively actuates one or more of said shapingelements so as to reversibly and controllably produce movement in atleast one of said joints, wherein a locking mechanism is provided forreleasable locking two adjacent segments together, wherein the lockingmechanism comprises an annular collar formed on an inner wall of thesocket of a first segment, and one or more addressable controllers forresistively heating the annular collar; wherein the collar is comprisedof a shape memory alloy which recovers a memorized shape when itundergoes a phase transformation between a first state and a secondstate; wherein the collar defines an inner diameter at the open end ofthe socket, and the collar has a diameter in said a first state which issmaller than a diameter of the collar in said second state; and whereinresistive heating of the collar by the addressable controllers causesthe shape memory alloy of the collar to transform from one of saidstates to the other of said states.
 2. The controllable robotic armaccording to claim 1, wherein each of the segments comprises a ball atits first end and a socket at its second end, the sockets of thesegments having a diameter sufficient to receive the balls of thesegments.
 3. The controllable robotic arm according to claim 2, whereinthe balls and sockets have a hyperbolic shape.
 4. The controllablerobotic arm according to claim 1, wherein the segments are annular andare each provided with a central, axially extending aperture, theapertures of the segments aligning to form a central passage extendingbetween a proximal end and a distal end of the articulable column, andwherein the compression element comprises an elongate tensioning elementextending through said central passage and having a first end located atthe proximal end of the articulable column and a second end fixed to oneof the segments spaced from the proximal end of the articulable column,wherein the first end of the tensioning element is attached to saidcompression control mechanism, and wherein the compression controlmechanism controls the tension in the tensioning element.
 5. Thecontrollable robotic arm according to claim 4, wherein the tensioningelement is a cable and the compression control mechanism includes meansfor increasing tension in the cable.
 6. The controllable robotic armaccording to claim 4, wherein the tensioning element is comprised of ashape memory alloy and is shorter in its heated, austenitic state thanin its cooler, martensitic state, and wherein the compression controlmechanism includes means for heating the tensioning element to atemperature at which at least a portion of the shape memory alloy istransformed to austenite.
 7. The controllable robotic arm according toanyone of claims 4 to 6, comprising at least two of said tensioningelements, a first one of which has a hollow interior, and a second oneof which extends through the hollow interior of the first tensioningelement, wherein the second tensioning element comprises a cable and hasa length which is equal to or greater than a length of the firsttensioning element.
 8. The controllable robotic arm according to claim7, wherein the first tensioning element has a variable modulus so as tobe more flexible at its distal end.
 9. The controllable robotic armaccording to claim 1, including a plurality of said shaping elementsextending along an outer surface of the articulable column.
 10. Thecontrollable robotic arm according to claim 9, wherein a plurality ofthe shaping elements comprises a hollow spring mounted between a pair ofannular retaining plates, wherein one of the retaining plates is mountedto an end of a cylindrical communicating tube, and wherein thearticulable column extends through said shaping elements.
 11. Thecontrollable robotic arm according to claim 10, wherein the retainingplates of each shaping element are connected together by cables at oneor more points around their circumference, at least one of the cablesbeing controlled by said compression control mechanism so as to producean off-centre compression or expansion force in said spring and therebycause bending of said shaping element.
 12. The controllable robotic armaccording to claim 10, wherein the shaping elements are rotatable aboutan axis of rotation which is parallel to the longitudinal axis of atleast one of the segments.
 13. The controllable robotic arm according toclaim 10, wherein an inner diameter of the shaping elements is variedsuch that the shaping elements are nestable with one another, such thatthe coil spring of a first shaping element is received inside thecylindrical communicating tube of a second shaping element, and whereinbending of the spring of the first element causing bending of the tubeof the second shaping element.
 14. The controllable robotic armaccording to claim 10, wherein the hollow spring is a coil spring or anexpandable mesh spring.
 15. The controllable robotic arm according toclaim 1, wherein a plurality of said shaping elements are comprised ofmicroelectronic mechanical devices (MEMS) and wherein the shape controlmechanism comprises a plurality of addressable controllers attached toor embedded in said MEMS devices, a computer which controls actuation ofsaid MEMS devices, and one or more conduits or a signal bus throughwhich the MEMS devices are connected to said computer.
 16. Thecontrollable robotic arm according to claim 15, wherein each of theshaping elements comprises an element which is variable in shape and/orlength, and which extends across at least one of said joints of thearticulable column.
 17. The controllable robotic arm according to claim16, wherein each of the shaping elements is comprised of a materialselected from electro-active polymers and shape memory alloys and eitherpartly or completely surrounds said at least one joint.
 18. Thecontrollable robotic arm according to claim 1, wherein a proximal end ofthe robotic arm is connected to a telescoping member received within anarticulating ball actuator.
 19. The controllable robotic arm accordingto claim 1, wherein a distal end of the robotic arm is provided with aconnector for attaching a tool.
 20. The controllable robotic armaccording to claim 1, wherein said robotic arm comprises two or more ofsaid articulable columns joined end to end, wherein an electromagneticconnector is provided between the joined ends of the columns and isactuated during joining of the columns.
 21. The controllable robotic armaccording to claim 1, wherein said first state is an austenitic stateand the second state is a martensitic state; and wherein heating of thecollar to the austenitic state causes the collar to constrict and engagethe outer surface of the ball of a second, adjacent segment.
 22. Thecontrollable robotic arm according to claim 21, wherein the lockingmechanism further comprises an annular groove formed in a base portionof the ball of the second segment; wherein the diameter of the collar inthe martensitic state is greater than a maximum diameter of the ball;and wherein the diameter of the collar in the austenitic state is lessthan a diameter of a base portion of the ball, such that the collar,when heated to its austenitic state, becomes locked in the groove of theball.
 23. The controllable robotic arm according to claim 21, whereineach of the segments of the articulable column is provided with saidlocking mechanism, such that the locking mechanisms comprise thecompression elements of the robotic arm, wherein the diameter of thecollar in the martensitic state is less than a maximum diameter of theball and greater than a diameter of the base portion of the ball; suchthat heating of the collar to its austenitic state causes the ball to bedrawn into the socket, thereby compressing the joint between the balland the socket.
 24. The controllable robotic arm according to claim 1,wherein said first state is a martensitic state and the second state isan austenitic state; and wherein heating of the collar to the austeniticstate causes the, collar to expand.